I Customize Display Template for Content By Search result Web Part. Then, Add a reference to your custom managed property in the display template to the ManagedPropertyMapping attribute.
But, when I Create a placeholder in the body of the Item display template for the managed property using syntax like:
ctx.CurrentItem.MyManagedProperty
ctx command return null, because regular columns will not automatically become managed properties when they are crawled.
How regular columns (not Site columns) become managed properties?